Selenophene π ‐Bridge Enables Balanced Ambipolar Transport in High‐Performance Organic Electrochemical Transistors

ABSTRACT Developing single‐component ambipolar organic mixed ionic‐electronic conductors (OMIECs) is crucial for realizing low‐power complementary circuits and biosensors based on organic electrochemical transistors (OECTs). However, there is a shortage of high‐performance single‐component ambipolar OMIECs, along with the issue of performance mismatch between p‐type and n‐type. Here, we copolymerized diketopyrrolopyrrole with selenophene serving as the π ‐bridge to synthesize a new ambipolar polymer, P(gTDPPSe). The selenophene π ‐bridge endows the polymer with favorable doping energy levels and a narrow bandgap, enabling P(gTDPPSe) to possess balanced ambipolar transport. Vertical OECTs of P(gTDPPSe) were fabricated, which demonstrate balanced and remarkable performance in both p‐type and n‐type modes, achieving peak transconductance of 192.9 and 117.6 mS, respectively. Notably, the peak I _ON of 57.3 mA ( V _DS = −0.5 V, V _G = −1.0 V) in p‐type mode is the highest among reported single‐component ambipolar materials. Building upon this, the P(gTDPPSe)‐based inverter achieved a maximum gain as high as 163 V/V. In this study, selenophene π ‐bridge enables precise control over molecular energy levels, planarity, and packing, yielding a high‐performance balanced ambipolar copolymer. This presents a feasible approach to acquire balanced single‐component ambipolar materials.